Something weird just happened to my skeleton and I wasn't able to reproduce.
After selecting a specific bone, every other action I did —like renaming a bone— caused it to be scaled by something like 80%. I recorded a video to better explain the issue:
http://take.ms/Fy811
(or if it doesn't work: https://monosnap.com/file/Zkqhv18wQ3GcawSpXUdFJGjmX8dDG2 )
I uploaded a log file as well, although I'm not entirely sure it refers to the same session. I made sure to upload the log before closing the editor while the bug was happening, so it wouldn't be overwritten.
